After the "While Guthix Sleeps" quest some of the Slayer masters are replaced for obvious reasons. The Slayer guide is missing those new masters:

 

 

 

Burthrope Slayer Master:

 

Turael is replaced with Spria

 

 

 

 

Shilo Village Slayer Master:

 

Duradel is replaced with Lapalok

 

 

 

 

The only changes are npc model and name, chat options remain the same. Lapalok will still provide a Slayer Skillcape and Spria will make blessed hatchets (from animal magnetism quest).

I believe I saw an old post about it from a crew member where they spoke of leaving it that way on purpose...

 

 

 

I think it was a decision they made very early into the release of WGS. Perhaps a crew member remembers the exact wording and reasoning?

 

The Crew considered this very carefully when the quest was released, and decided not to make this change. For one, it would spoiler the While Guthix Sleeps quest for the many, many folks that can't do it yet. Two, it would affect many places on the website. And three, any player who is high enough to complete WGS can figure out that the name has changed but "the song remains the same".

 

 

 

 

I think that may be the post to which SportsGuy was referring.

 

For the reasons above, it doesn't seem like we'll be changing this any time soon.

 

Nonetheless, your effort is greatly appreciated. :)